It is known to provide aircraft, particularly unmanned aircraft, with an automatic flight control such as an autopilot. It is further known to assign an air corridor to such aircraft, said corridor e.g. corresponding to a reserved airspace. So as to remain in the reserved or assigned airspace, an automatic flight control can be provided with sensors determining a flight altitude and/or a global position (e.g. with a satellite navigation system being used) of the aircraft in order to control the aircraft within the assigned airspace on the basis of the sensor data.
In particular, such a restriction to an assigned airspace may result from requirements of the aviation law to be met. For instance, an aircraft to which a cylindrical airspace has been assigned may on no account leave this airspace upwards as, there, other air traffic may take place and may otherwise be adversely affected by the aircraft.
When errors occur in the automatic flight control, the aircraft may leave the assigned airspace and may e.g. have an adverse effect on air traffic, which could entail serious damage.
Examples of such errors are defective sensors, calculation errors and defective signals of a satellite navigation system used.
Therefore, the invention indicated in claim 1 is based on the object of preventing leaving the assigned airspace when errors occur in the automatic flight control, thereby reducing a risk potential of an aircraft.